Open Data supplied by Natural Environment Research Council (NERC)

RRS Discovery 267 150kHz VMADCP - MVBS

Deployment and originator's processing

Two RDI Vessel-Mounted Acoustic Doppler Current Profilers (VM-ADCPs) were operated on Discovery 267; the 150kHz VM-ADCP and the 75 kHz Phased Array instrument (Ocean Surveyor) that had been fitted immediately prior to FISHES (Discovery 253, May-June 2001). The 150 kHz ADCP is mounted in the hull 1.75 m to port of the keel, 33 m aft of the bow at the waterline and at an approximate depth of 5 m. The 75 kHz ADCP is mounted in a second well in the hull, but 4.15 m forward and 2.5 m to starboard of the 150 kHz well. The following table describes the setup of the 150kHz ADCP.

Frequency dependent constant

4.17e5

Power into water (W)

183.15

Dimensionless noise factor

8.95

Bin length (m)

4

Blanking distance (m)

4

A nominal calibration of *0.42 was applied to the raw backscatter data by the data originator.

BODC processing

A total of 41 files were submitted to BODC. The data were supplied in P* binary format. The following variables were transferred to BODC QXF format (a BODC-defined subset of NetCDF and BODC's format for 2 dimensionsal datacycle storage) using transfer process tr363. The only variables not transferred were the non-calibrated backscatter and the time channel (the latter being automatically calculated by the transfer program).

BODC Code

Description

Units

Originator's variable

ALATZZ01

Latitude

degrees

lat

ALONZZ01

Longitude

degrees

lon

DSRNGR01

Distance Run

km

distrun

DBINAA01

Bin depth

metres

bindepth

ACBSA150

Absolute backscatter (MVBS)

decibels

amplcal

PCGDAP01

Percentage good returm signal

%

good

Screening and Data quality

The data have been visually screened for obvious problems using the BODC EDSERPLO software. No significant problems were detected.

Marine Productivity programme (MarProd)

The Marine Productivity programme (MarProd) was a Thematic Programme of the Natural Environment Research Council. It was funded for a period of five years starting in 2000. Its main goal was "to develop coupled modelling and observation systems for the pelagic ecosystem, with emphasis on physical factors affecting zooplankton dynamics" with the following specific objectives:

To identify the dominant spatial and temporal scales of physical parameters and zooplankton population dynamics, by observation, modelling and retrospective analysis

To parameterise the critical processes governing zooplankton dynamics by observations and experiments

To construct and validate spatially explicit models of zooplankton and their food and predators, capable of resolving short term changes in population structure

To provide data for model validation by developing and applying new interdisciplinary techniques to a wide spectrum of biological and physical parameters

To develop a database and information system for historic and new data and models.

The programme was composed of two phases: Phase 1 projects (2000-2002) focused on the use of historical datasets and existing biological models, complemented by laboratory experiments and remote-sensing analyses to gain a better understanding of the dynamics of zooplankton populations in shelf seas. The main, field-based Phase 2 of the programme (2001-2005) focused on the open ocean. The fieldwork phase took place between November 2001 and December 2002 and consisted of four surveys in the northern North Atlantic in early winter 2001 and 2002, and in spring and summer 2002.

MarProd was a major UK contribution to the international Global Ocean Ecosystem Dynamics project (GLOBEC).